1. Field of the Invention
The present invention relates to an image forming apparatus of a type that includes a plurality of image bearing bodies.
2. Description of Related Art
As an example of the image forming apparatus of this type, there has conventionally been known an image forming apparatus that includes: a photosensitive member, a plurality of developing devices, and an intermediate transferring member. The plurality of developing devices contain toner in a plurality of different colors, respectively. Each developing device includes a developing roller. The photo 16 member (image bearing body) bears visible images in respective colors, which have been developed by toner supplied from the developing rollers. The visible images in the respective colors are transferred to the intermediate transferring member (another image bearing body) and are superimposed one on another on the intermediate transferring member. In this way, the intermediate transferring member bears a resultant multi-color image. The multicolor image is then transferred from the intermediate transferring member onto a sheet. The representative examples of the photosensitive member include a photosensitive drum and a photosensitive belt.
A cleaning device is ordinarily provided in such a type of color laser printer. The cleaning device removes, from the photosensitive member, residual toner that remains on the photosensitive member after the visible images are transferred from the photosensitive member onto the intermediate transferring member. An additional cleaning apparatus is provided for removing, from the intermediate transferring member, residual toner that remains on the intermediate transferring member after the color image is transferred from the intermediate transferring member onto the sheet.
In one example, a photosensitive-member cleaning roller is provided to contact the surface of the photosensitive member. Waste toner captured by the surface of the photosensitive member cleaning roller is accumulated in a waste toner reserving portion that is provided in proximity to the photosensitive-member cleaning roller. An intermediate-transferring-member cleaning roller is additionally provided to contact the surface of the intermediate transferring member. Waste toner captured by the surface of the intermediate-transferring-member cleaning roller is accumulated in another water toner reserving portion that is provided in proximity to the intermediate-transferring-member cleaning roller.
In this way, two waste toner cases are provided in the color laser printer. However, in such a case, it becomes difficult to reduce the size of the entire apparatus. It is required to perform a cumbersome maintenance work such as discharging of toner accumulated in the two different waste toner cases.
In view of these problems, there has been proposed a method for first returning the toner captured by the surface of the photosensitive-member cleaning roller back to the photosensitive member at a timing other than the period, during which image forming operations is performed on the photosensitive member. Then, the waste toner is transferred from the photosensitive member onto the intermediate transferring member. Following this, the waste toner that is now on the intermediate transferring member is captured by the intermediate-transferring-member cleaning roller and is collected in a waste toner reserving portion that is provided in proximity to the intermediate-transferring-member cleaning roller. With this method, it becomes possible to collect the waste toner at one place. It becomes relatively easy to reduce the size of the apparatus. The maintenance work becomes easier.
With the above-described conventional method, the toner captured by the photosensitive member cleaning roller is carried to the waste toner reserving portion through the photosensitive member and the intermediate transferring member. Accordingly, the photosensitive member will possibly be stained with the waste toner.
Additionally, the transferring ratio of toner from the photosensitive member to the intermediate transferring member is not always 100%. In other words, the entire amount of toner on the photosensitive-member may not be completely transferred from the photosensitive member to the intermediate transferring member. Accordingly, the waste toner may not be collected with high recovery efficiency.
In view of the above-described drawbacks, it is an objective of the present invention to provide an improved image forming apparatus that includes a plurality of image bearing bodies and that can efficiently collect residual toner remaining on the plurality of image bearing bodies at a single, common place.
In order to attain the above and other objects, the present invention provides an image forming apparatus comprising: a first image bearing member that is capable of bearing a toner image on its surface, the first image bearing member moving to convey the toner image from a developing portion to a first transfer position; a second image bearing member that is capable of bearing a toner image on its surface, the second image bearing member receiving the toner image transferred from the first image bearing member at the first transfer position and moving to convey the toner image to a second transfer position; a transfer unit transferring the toner image from the second image bearing member to an image recording medium at the second transfer position; a first cleaning unit removing, from the first image bearing member, residual toner that remains on the first image bearing member after the toner image is transferred to the second image bearing member, the first cleaning unit discharging the removed toner onto the second image bearing member; and a second cleaning unit removing, from the second image bearing member, residual toner that remains on the second image bearing member after the toner image is transferred from the second image bearing member to the image recording medium, the second cleaning unit removing, from the second image bearing member, the toner discharged from the first cleaning unit.